Extension of Phase Correlation to Subpixel （扩展相位相关的亚像素）.pdfVIP

Extension of Phase Correlation to Subpixel Registration Hassan Foroosh (Shekarforoush), Josiane B. Zerubia, Senior Member, IEEE, and Marc Berthod Abstract—In this paper, we have derived analytic expressions proach is to relate the temporal derivatives of the sequence to the for the phase correlation of downsampled images. We have shown spatial derivatives of the reference frame using the so called gra- that for downsampled images the signal power in the phase corre- dient constraint equation under intensity conservation assump- lation is not concentrated in a single peak, but rather in several co- herent peaks mostly adjacent to each other. These coherent peaks tion [10], [11], [17]. Due to the intensity conservation assump- correspond to the polyphase transform of a filtered unit impulse tion, these methods often require that the inter-frame displace- centered at the point of registration. The analytic results provide ments to be relatively small compared to the intensity gradi- a closed-form solution to subpixel translation estimation, and are ents of the reference frame. Also, to reduce the sensitivity of used for detailed error analysis. Excellent results have been ob- tained for subpixel translation estimation of images of different na- the derivative operators to the noise process, in general, some ture and across different spectral bands. regularization is required and the gradient constraint is com- bined within some local neighborhood of each pixel. However, Index Terms—Image alignment, phase correlation, subpixel reg- istration.